Optical imaging lens and electronic device comprising the same

ABSTRACT

An optical imaging lens includes six lens elements. The object-side surface of the first lens element has a convex part in a vicinity of the periphery of the first lens element, the image-side surface of the second lens element has a concave part in a vicinity of the periphery of the first lens element, the object-side surface of the third lens element has a convex part in a vicinity of the optical axis, the image-side surface of the fourth lens element has a convex part in a vicinity of the periphery of the fourth lens element, the image-side surface of the fifth lens element has a concave part in a vicinity of the optical axis, and the sixth lens element has negative refractive power.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/915,376, filed Jun. 29, 2020, which is a continuation of U.S. patentapplication Ser. No. 16/866,282, filed May 4, 2020, now U.S. Pat. No.11,231,564, which is a continuation of U.S. patent application Ser. No.16/594,426, filed on Oct. 7, 2019, now U.S. Pat. No. 10,684,451, whichis a continuation of U.S. patent application Ser. No. 16/029,330, filedon Jul. 6, 2018, now U.S. Pat. No. 10,473,898, which is a continuationof U.S. patent application Ser. No. 15/092,417, filed on Apr. 6, 2016,now U.S. Pat. No. 10,048,467, which is a continuation of U.S. patentapplication Ser. No. 14/521,461, filed on Oct. 23, 2014, now U.S. Pat.No. 9,335,518, which claims priority from P.R.C. Patent Application No.201410366295.4, filed on Jul. 29, 2014, the contents of which are herebyincorporated by reference in their entirety for all purposes.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention generally relates to an optical imaging lens setand an electronic device which includes such optical imaging lens set.Specifically speaking, the present invention is directed to an opticalimaging lens set of six lens elements and an electronic device whichincludes such optical imaging lens set of six lens elements.

2. Description of the Prior Art

In recent years, the popularity of mobile phones and digital camerasmakes photography modules (including optical imaging lens set, holderand sensor, etc) well developed. Mobile phones and digital camerasbecome lighter and thinner, so that the miniaturization demands ofphotography modules get higher and higher. As the charge coupled device(CCD) or complementary metal-oxide semiconductor (CMOS) technologiesadvance, the size of the photography modules can be shrunk too, butthese photography modules still need to maintain good imaging quality.

Conventional optical imaging lens sets are mostly with only four lenselements, and since they have fewer lens elements, the total length ofthe optical imaging lens set is relatively short. However, as therequirements of good imaging quality increase, the conventional opticalimaging lens set of four lens elements can hardly satisfy theserequirements. U.S. Pat. Nos. 7,663,814 and 8,040,618 disclose an opticalimaging lens set of six lens elements respectively, and all of the totallength (the distance between the first object surface of the first lenselement to an image plane) of the optical imaging lens sets are over 21mm. The size of the optical imaging lens set is too big to satisfy thespecification requirements of consumer electronics products. Therefore,a novel optical imaging lens set with small total length and goodimaging quality is needed.

SUMMARY OF THE INVENTION

In light of the above, the present invention proposes an optical imaginglens set that is lightweight has a low production cost, an enlarged halfof field of view, a high resolution and high image quality. The opticalimaging lens set of six lens elements of the present invention has afirst lens element, a second lens element, a third lens element, afourth lens element, a fifth lens element and a sixth lens elementsequentially from an object side to an image side along an optical axis.

The present invention provides an optical imaging lens set, from anobject side toward an image side in order along an optical axiscomprising: a first lens element, a second lens element, a third lenselement, a fourth lens element, a fifth lens element and a sixth lenselement. The first lens element has an image-side surface with a concavepart in a vicinity of its periphery. The second lens element has animage-side surface with a concave part in a vicinity of the opticalaxis. The third lens element has positive refractive power. The fourthlens element has an object-side surface with a convex part in a vicinityof its circular periphery. The fifth lens element has an object-sidesurface with a concave part in a vicinity of the optical axis. The sixthlens element having an image-side surface with a concave part in avicinity of the optical axis. Wherein the optical imaging lens set doesnot include any lens element with refractive power other than saidfirst, second, third, fourth, fifth and sixth lens elements.

In the optical imaging lens set of six lens elements of the presentinvention, an air gap G12 along the optical axis is disposed between thefirst lens element and the second lens element, an air gap G23 along theoptical axis is disposed between the second lens element and the thirdlens element, an air gap G34 along the optical axis is disposed betweenthe third lens element and the fourth lens element, an air gap G45 alongthe optical axis is disposed between the fourth lens element and thefifth lens element, an air gap G56 along the optical axis is disposedbetween the fifth lens element and the sixth lens element, and the sumof total five air gaps between adjacent lens elements from the firstlens element to the sixth lens element along the optical axis is AAG,AAG=G12+G23+G34+G45+G56.

In the optical imaging lens set of six lens elements of the presentinvention, the first lens element has a first lens element thickness T1along the optical axis, the second lens element has a second lenselement thickness T2 along the optical axis, the third lens element hasa third lens element thickness T3 along the optical axis, the fourthlens element has a fourth lens element thickness T4 along the opticalaxis, the fifth lens element has a fifth lens element thickness T5 alongthe optical axis, the sixth lens element has a sixth lens elementthickness T6 along the optical axis, and the total thickness of all thelens elements in the optical imaging lens set along the optical axis isALT, ALT=T1+T2+T3+T4+T5+T6.

In addition, the distance between the image-side surface of the sixthlens element to an image plane along the optical axis is BFL (back focallength); the effective focal length of the optical imaging lens set isEFL.

In the optical imaging lens set of six lens elements of the presentinvention, the relationship (G12+G34)/T6≤1.7 is satisfied.

In the optical imaging lens set of six lens elements of the presentinvention, the relationship T2/T3≤1.5 is satisfied.

In the optical imaging lens set of six lens elements of the presentinvention, the relationship 3≤EFL/G23≤11 is satisfied.

In the optical imaging lens set of six lens elements of the presentinvention, the relationship 0.9≤EFL/AAG≤2.6 is satisfied.

In the optical imaging lens set of six lens elements of the presentinvention, the relationship AAG/BFL≤2.1 is satisfied.

In the optical imaging lens set of six lens elements of the presentinvention, the relationship 2.8≤EFL/T2 is satisfied.

In the optical imaging lens set of six lens elements of the presentinvention, the relationship 1.88≤BFL/(G34+G45)≤6 is satisfied.

In the optical imaging lens set of six lens elements of the presentinvention, the relationship AAG/BFL≤2.1 is satisfied.

In the optical imaging lens set of six lens elements of the presentinvention, the relationship 1.5≤BFL/T1 is satisfied.

In the optical imaging lens set of six lens elements of the presentinvention, the relationship 1.4≤BFL/T2 is satisfied.

In the optical imaging lens set of six lens elements of the presentinvention, the relationship 1.9≤BFL/T2 is satisfied.

In the optical imaging lens set of six lens elements of the presentinvention, the relationship AAG/T3·3.3 is satisfied.

In the optical imaging lens set of six lens elements of the presentinvention, the relationship 4.7≤EFL/T1 is satisfied.

In the optical imaging lens set of six lens elements of the presentinvention, the relationship 1.1≤T6/T2 is satisfied.

In the optical imaging lens set of six lens elements of the presentinvention, the relationship AAG/T4≤2.8 is satisfied.

In the optical imaging lens set of six lens elements of the presentinvention, the relationship 3.5≤EFL/G23≤11 is satisfied.

The present invention also proposes an electronic device which includesthe optical imaging lens set as described above. The electronic deviceincludes a case and an image module disposed in the case. The imagemodule includes an optical imaging lens set as described above, a barrelfor the installation of the optical imaging lens set, a module housingunit for the installation of the barrel, a substrate for theinstallation of the module housing unit, and an image sensor disposed onthe substrate and at an image side of the optical imaging lens set.

These and other objectives of the present invention will no doubt becomeobvious to those of ordinary skill in the art after reading thefollowing detailed description of the preferred embodiment that isillustrated in the various figures and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a first example of the optical imaging lens set ofthe present invention.

FIG. 2A illustrates the longitudinal spherical aberration on the imageplane of the first example.

FIG. 2B illustrates the astigmatic aberration on the sagittal directionof the first example.

FIG. 2C illustrates the astigmatic aberration on the tangentialdirection of the first example.

FIG. 2D illustrates the distortion aberration of the first example.

FIG. 3 illustrates a second example of the optical imaging lens set ofsix lens elements of the present invention.

FIG. 4A illustrates the longitudinal spherical aberration on the imageplane of the second example.

FIG. 4B illustrates the astigmatic aberration on the sagittal directionof the second example.

FIG. 4C illustrates the astigmatic aberration on the tangentialdirection of the second example.

FIG. 4D illustrates the distortion aberration of the second example.

FIG. 5 illustrates a third example of the optical imaging lens set ofsix lens elements of the present invention.

FIG. 6A illustrates the longitudinal spherical aberration on the imageplane of the third example.

FIG. 6B illustrates the astigmatic aberration on the sagittal directionof the third example.

FIG. 6C illustrates the astigmatic aberration on the tangentialdirection of the third example.

FIG. 6D illustrates the distortion aberration of the third example.

FIG. 7 illustrates a fourth example of the optical imaging lens set ofsix lens elements of the present invention.

FIG. 8A illustrates the longitudinal spherical aberration on the imageplane of the fourth example.

FIG. 8B illustrates the astigmatic aberration on the sagittal directionof the fourth example.

FIG. 8C illustrates the astigmatic aberration on the tangentialdirection of the fourth example.

FIG. 8D illustrates the distortion aberration of the fourth example.

FIG. 9 illustrates a fifth example of the optical imaging lens set ofsix lens elements of the present invention.

FIG. 10A illustrates the longitudinal spherical aberration on the imageplane of the fifth example.

FIG. 10B illustrates the astigmatic aberration on the sagittal directionof the fifth example.

FIG. 10C illustrates the astigmatic aberration on the tangentialdirection of the fifth example.

FIG. 10D illustrates the distortion aberration of the fifth example.

FIG. 11 illustrates a sixth example of the optical imaging lens set ofsix lens elements of the present invention.

FIG. 12A illustrates the longitudinal spherical aberration on the imageplane of the sixth example.

FIG. 12B illustrates the astigmatic aberration on the sagittal directionof the sixth example.

FIG. 12C illustrates the astigmatic aberration on the tangentialdirection of the sixth example.

FIG. 12D illustrates the distortion aberration of the sixth example.

FIG. 13 illustrates a seventh example of the optical imaging lens set ofsix lens elements of the present invention.

FIG. 14A illustrates the longitudinal spherical aberration on the imageplane of the seventh example.

FIG. 14B illustrates the astigmatic aberration on the sagittal directionof the seventh example.

FIG. 14C illustrates the astigmatic aberration on the tangentialdirection of the seventh example.

FIG. 14D illustrates the distortion aberration of the seventh example.

FIG. 15 illustrates exemplificative shapes of the optical imaging lenselement of the present invention.

FIG. 16 illustrates a first preferred example of the portable electronicdevice with an optical imaging lens set of the present invention.

FIG. 17 illustrates a second preferred example of the portableelectronic device with an optical imaging lens set of the presentinvention.

FIG. 18 shows the optical data of the first example of the opticalimaging lens set.

FIG. 19 shows the aspheric surface data of the first example.

FIG. 20 shows the optical data of the second example of the opticalimaging lens set.

FIG. 21 shows the aspheric surface data of the second example.

FIG. 22 shows the optical data of the third example of the opticalimaging lens set.

FIG. 23 shows the aspheric surface data of the third example.

FIG. 24 shows the optical data of the fourth example of the opticalimaging lens set.

FIG. 25 shows the aspheric surface data of the fourth example.

FIG. 26 shows the optical data of the fifth example of the opticalimaging lens set.

FIG. 27 shows the aspheric surface data of the fifth example.

FIG. 28 shows the optical data of the sixth example of the opticalimaging lens set.

FIG. 29 shows the aspheric surface data of the sixth example.

FIG. 30 shows the optical data of the seventh example of the opticalimaging lens set.

FIG. 31 shows the aspheric surface data of the seventh example.

FIG. 32 shows some important ratios in the examples.

DETAILED DESCRIPTION OF THE INVENTION

Before the detailed description of the present invention, the firstthing to be noticed is that in the present invention, similar (notnecessarily identical) elements are labeled as the same numeralreferences. In the entire present specification, “a certain lens elementhas negative/positive refractive power” refers to the part in a vicinityof the optical axis of the lens element has negative/positive refractivepower. “An object-side/image-side surface of a certain lens element hasa concave/convex part” refers to the part is more concave/convex in adirection parallel with the optical axis to be compared with an outerregion next to the region. Taking FIG. 15 for example, the optical axisis “I” and the lens element is symmetrical with respect to the opticalaxis I. The object side of the lens element has a convex part in theregion A, a concave part in the region B, and a convex part in theregion C because region A is more convex in a direction parallel withthe optical axis than an outer region (region B) next to region A,region B is more concave than region C and region C is similarly moreconvex than region E. “A circular periphery of a certain lens element”refers to a circular periphery region of a surface on the lens elementfor light to pass through, that is, region C in the drawing. In thedrawing, imaging light includes Lc (chief ray) and Lm (marginal ray). “Avicinity of the optical axis” refers to an optical axis region of asurface on the lens element for light to pass through, that is, theregion A in FIG. 15 . In addition, the lens element may include anextension part E for the lens element to be installed in an opticalimaging lens set. Ideally speaking, no light would pass through theextension part, and the actual structure and shape of the extension partis not limited to this and may have other variations. For the reason ofsimplicity, the extension part is not illustrated in FIGS. 1, 3, 5, 7,9, 11 and 13 .

As shown in FIG. 1 , the optical imaging lens set 1 of six lens elementsof the present invention, sequentially located from an object side 2(where an object is located) to an image side 3 along an optical axis 4,has a first lens element 10, a second lens element 20, a third lenselement 30, a fourth lens element 40, a fifth lens element 50, a sixthlens element 60, a filter 72 and an image plane 71. Generally speaking,the first lens element 10, the second lens element 20, the third lenselement 30, the fourth lens element 40, the fifth lens element 50 andthe sixth lens element 60 maybe made of a transparent plastic materialand each has an appropriate refractive power, but the present inventionis not limited to this. There are exclusively six lens elements withrefractive power in the optical imaging lens set 1 of the presentinvention. The optical axis 4 is the optical axis of the entire opticalimaging lens set 1, and the optical axis of each of the lens elementscoincides with the optical axis of the optical imaging lens set 1.

Furthermore, the optical imaging lens set 1 includes an aperture stop(ape. stop) 80 disposed in an appropriate position. In FIG. 1 , theaperture stop 80 is disposed between the third lens element 30 and thefourth lens element 40. When light emitted or reflected by an object(not shown) which is located at the object side 2 enters the opticalimaging lens set 1 of the present invention, it forms a clear and sharpimage on the image plane 71 at the image side 3 after passing throughthe first lens element 10, the second lens element 20, the third lenselement 30, the aperture stop 80, the fourth lens element 40, the fifthlens element 50, the sixth lens element 60 and the filter 72.

In the embodiments of the present invention, the optional filter 72 maybe a filter of various suitable functions, for example, the filter 72may be an infrared cut filter (IR cut filter), placed between the sixthlens element 60 and the image plane 71. The filter 72 is made of glass.

Each lens element in the optical imaging lens set 1 of the presentinvention has an object-side surface facing toward the object side 2 aswell as an image-side surface facing toward the image side 3. Forexample, the first lens element 10 has a first object-side surface 11and a first image-side surface 12; the second lens element 20 has asecond object-side surface 21 and a second image-side surface 22; thethird lens element 30 has a third object-side surface 31 and a thirdimage-side surface 32; the fourth lens element 40 has a fourthobject-side surface 41 and a fourth image-side surface 42; the fifthlens element 50 has a fifth object-side surface 51 and a fifthimage-side surface 52; and the sixth lens element 60 has a sixthobject-side surface 61 and a sixth image-side surface 62. In addition,each object-side surface and image-side surface in the optical imaginglens set 1 of the present invention has a part in a vicinity of itscircular periphery (circular periphery part) away from the optical axis4 as well as a part in a vicinity of the optical axis (optical axispart) close to the optical axis 4.

Each lens element in the optical imaging lens set 1 of the presentinvention further has a central thickness on the optical axis 4. Forexample, the first lens element 10 has a first lens element thicknessT1, the second lens element 20 has a second lens element thickness T2,the third lens element 30 has a third lens element thickness T3, thefourth lens element 40 has a fourth lens element thickness T4, the fifthlens element 50 has a fifth lens element thickness T5, and the sixthlens element 60 has a sixth lens element thickness T6. Therefore, thetotal thickness of all the lens elements in the optical imaging lens set1 along the optical axis 4 is ALT, ALT=T1+T2+T3+T4+T5+T6.

In addition, between two adjacent lens elements in the optical imaginglens set 1 of the present invention there is an air gap along theoptical axis 4. For example, an air gap G12 is disposed between thefirst lens element 10 and the second lens element 20, an air gap G23 isdisposed between the second lens element 20 and the third lens element30, an air gap G34 is disposed between the third lens element 30 and thefourth lens element 40, an air gap G45 is disposed between the fourthlens element 40 and the fifth lens element 50, and an air gap G56 isdisposed between the fifth lens element 50 and the sixth lens element60. Therefore, the sum of total five air gaps between adjacent lenselements from the first lens element 10 to the sixth lens element 60along the optical axis 4 is AAG, AAG=G12+G23+G34+G45+G56.

In addition, the distance between the first object-side surface 11 ofthe first lens element 10 to the image plane 71, namely the total lengthof the optical imaging lens set along the optical axis 4 is TTL; theeffective focal length of the optical imaging lens set is EFL; thedistance between the sixth image-side surface 62 of the six lens element60 to the image plane 71 along the optical axis 4 is BFL; the distancebetween the sixth image-side surface 62 of the six lens element 60 tothe filter 72 along the optical axis 4 is G6F; the thickness of thefilter 72 along the optical axis 4 is TF; the distance between thefilter 72 to the image plane 71 along the optical axis 4 is GFP;Therefore, BFL=G6F+TF+GFP.

First Example

Please refer to FIG. 1 which illustrates the first example of theoptical imaging lens set 1 of the present invention. Please refer toFIG. 2A for the longitudinal spherical aberration on the image plane 71of the first example; please refer to FIG. 2B for the astigmatic fieldaberration on the sagittal direction; please refer to FIG. 2C for theastigmatic field aberration on the tangential direction, and pleaserefer to FIG. 2D for the distortion aberration. The Y axis of thespherical aberration in each example is “field of view” for 1.0. The Yaxis of the astigmatic field and the distortion in each example standfor “Half Field of View (HFOV)”, HFOV stands for the half field of viewwhich is half of the field of view of the entire optical lens elementsystem. The HFOV is 66.5 degrees.

The optical imaging lens set 1 of the first example has six lenselements 10 to 60 are made of a plastic material and have refractivepower. The optical imaging lens set 1 also has an aperture stop 80, afilter 72, and an image plane 71. The aperture stop 80 is providedbetween the third lens element 30 and the fourth lens element 40. Thefilter 72 may be used for preventing specific wavelength light (such asthe infrared light) reaching the image plane to adversely affect theimaging quality.

The first lens element 10 has negative refractive power. The firstobject-side surface 11 facing toward the object side 2 is a convexsurface, having a convex part 13 in the vicinity of the optical axis anda convex part 14 in a vicinity of its circular periphery. The firstimage-side surface 12 facing toward the image side 3 is a concavesurface, having a concave part 16 in the vicinity of the optical axisand a concave part 17 in a vicinity of its circular periphery. Besides,the first object-side surface 11 of the first lens element 10 is aspherical surface, and the first image-side 12 of the first lens element10 is an aspherical surface.

The second lens element 20 has negative refractive power. The secondobject-side surface 21 facing toward the object side 2 has a convex part23 in the vicinity of the optical axis and a convex part 24 in avicinity of its circular periphery. The second image-side surface 22facing toward the image side 3 is a concave surface, having a concavepart 26 in the vicinity of the optical axis and a concave part 27 in avicinity of its circular periphery. Both the second object-side surface21 and the second image-side 22 of the second lens element 20 areaspherical surfaces.

The third lens element 30 has positive refractive power. The thirdobject-side surface 31 facing toward the object side 2 has a convex part33 in the vicinity of the optical axis and a convex part 34 in avicinity of its circular periphery. The third image-side surface 32facing toward the image side 3 is a convex surface, having a convex part36 in the vicinity of the optical axis and a convex part 37 in avicinity of its circular periphery. Both the third object-side surface31 and the third image-side 32 of the third lens element 30 areaspherical surfaces.

The fourth lens element 40 has positive refractive power. The fourthobject-side surface 41 facing toward the object side 2 is a convexsurface, having a convex part 43 in the vicinity of the optical axis anda convex part 44 in a vicinity of its circular periphery. The fourthimage-side surface 42 facing toward the image side 3 is a convexsurface, having a convex part 46 in the vicinity of the optical axis anda convex part 47 in a vicinity of its circular periphery. Both thefourth object-side surface 41 and the fourth image-side 42 of the fourthlens element 40 are aspherical surfaces.

The fifth lens element 50 has negative refractive power. The fifthobject-side surface 51 facing toward the object side 2 has a concavepart 53 in the vicinity of the optical axis and a concave part 54 in avicinity of its circular periphery. The fifth image-side surface 52facing toward the image side 3 has a concave part 56 in the vicinity ofthe optical axis and a concave part 57 in a vicinity of its circularperiphery. Both the fifth object-side surface 51 and the fifthimage-side 52 of the fifth lens element 50 are aspherical surfaces.

The sixth lens element 60 has negative refractive power. The sixthobject-side surface 61 facing toward the object side 2 has a convex part63 in the vicinity of the optical axis and a convex part 64 in avicinity of its circular periphery. The sixth image-side surface 62facing toward the image side 3 has a concave part 66 in the vicinity ofthe optical axis and a convex part 67 in a vicinity of its circularperiphery. Both the sixth object-side surface 61 and the sixthimage-side 62 of the sixth lens element 60 are aspherical surfaces. Thefilter 72 may be disposed between the sixth lens element 60 and theimage plane 71.

In the optical imaging lens element 1 of the present invention, exceptfor the first object-side surface 11, others object-side surfaces21/31/41/51/61 and image-side surfaces 12/22/32/42/52/62 are allaspherical. These aspheric coefficients are defined according to thefollowing formula:

${Z(Y)} = {\frac{Y^{2}}{R}/\left( {1 + \sqrt{\left. {1 - {\left( {1 + K} \right)\frac{Y^{2}}{R^{2}}}} \right) + {\sum\limits_{i = 1}^{n}{a_{2i} \times Y^{2i}}}}} \right.}$

In which:

R represents the curvature radius of the lens element surface;

Z represents the depth of an aspherical surface (the perpendiculardistance between the point of the aspherical surface at a distance Yfrom the optical axis and the tangent plane of the vertex on the opticalaxis of the aspherical surface);

Y represents a vertical distance from a point on the aspherical surfaceto the optical axis;

K is a conic constant; and a2i is the aspheric coefficient of the 2iorder.

The optical data of the first example of the optical imaging lens set 1are shown in FIG. 18 while the aspheric surface data are shown in FIG.19 . In the present examples of the optical imaging lens set, thef-number of the entire optical lens element system is Fno, HFOV standsfor the half field of view which is half of the field of view of theentire optical lens element system, and the unit for the curvatureradius, the thickness and the focal length is in millimeters (mm). Thelength of the optical imaging lens set (the distance from the firstobject-side surface 11 of the first lens element 10 to the image plane71) is 4.060 mm. HFOV is 66.5 degrees. Some important ratios of thefirst example are as follows:

(G12+G34)/T6=0.615 T2/T3=1.462 EFL/G23=3.848 EFL/AAG=1.466 AAG/BFL=2.078EFL/T2=4.326 BFL/(G34+G45)=1.651 BFL/T1=1.718 BFL/T2=1.420 AAG/T3=4.314EFL/T1=5.235 AAG/T4=1.867 T4/T2=1.580 T6/T2=1.332 Second Example

Please refer to FIG. 3 which illustrates the second example of theoptical imaging lens set 1 of the present invention. It is noted thatfrom the second example to the following examples, in order to simplifythe figures, only the components different from what the first examplehas and the basic lens elements will be labeled in figures. Otherscomponents that are the same as what the first example has, such as theobject-side surface, the image-side surface, the part in a vicinity ofthe optical axis and the part in a vicinity of its circular peripherywill be omitted in the following example. Please refer to FIG. 4A forthe longitudinal spherical aberration on the image plane 71 of thesecond example; please refer to FIG. 4B for the astigmatic aberration onthe sagittal direction; please refer to FIG. 4C for the astigmaticaberration on the tangential direction, and please refer to FIG. 4D forthe distortion aberration. The components in the second example aresimilar to those in the first example, but the optical data such as thecurvature radius, the refractive power, the lens thickness, the lensfocal length, the aspheric surface or the back focal length in thisexample are different from the optical data in the first example. Theoptical data of the second example of the optical imaging lens set areshown in FIG. 20 while the aspheric surface data are shown in FIG. 21 .The length of the optical imaging lens set is 4.584 mm. HFOV is 66.5degrees. Some important ratios of the second example are as follows:

(G12+G34)/T6=1.666 T2/T3=1.043 EFL/G23=3.749 EFL/AAG=0.981 AAG/BFL=3.198EFL/T2=5.526 BFL/(G34+G45)=1.591 BFL/T1=1.085 BFL/T2=1.761 AAG/T3=5.877EFL/T1=3.405 AAG/T4=2.773 T4/T2=2.031 T6/T2=1.595 Third Example

Please refer to FIG. 5 which illustrates the third example of theoptical imaging lens set 1 of the present invention. Please refer toFIG. 6A for the longitudinal spherical aberration on the image plane 71of the third example; please refer to FIG. 6B for the astigmaticaberration on the sagittal direction; please refer to FIG. 6C for theastigmatic aberration on the tangential direction, and please refer toFIG. 6D for the distortion aberration. The components in the thirdexample are similar to those in the first example, but the optical datasuch as the curvature radius, the refractive power, the lens thickness,the lens focal length, the aspheric surface or the back focal length inthis example are different from the optical data in the first example,and in this example, the fifth image-side surface 52 of the fifth lenselement 50 has a concave part 56A in the vicinity of the optical axisand a convex part 57A in a vicinity of its circular periphery; the sixthobject-side surface 61 of the fifth lens element 60 has a convex part63A in the vicinity of the optical axis and a concave part 64A in avicinity of its circular periphery. The optical data of the thirdexample of the optical imaging lens set are shown in FIG. 22 while theaspheric surface data are shown in FIG. 23 . The length of the opticalimaging lens set is 5.031 mm. HFOV is 66.5 degrees. Some importantratios of the third example are as follows:

(G12+G34)/T6=0.564 T2/T3=0.179 EFL/G23=8.019 EFL/AAG=2.322 AAG/BFL=1.045EFL/T2=8.404 BFL/(G34+G45)=3.383 BFL/T1=2.097 BFL/T2=3.464 AAG/T3=0.650EFL/T1=5.087 AAG/T4=1.434 T4/T2=2.524 T6/T2=1.000 Fourth Example

Please refer to FIG. 7 which illustrates the fourth example of theoptical imaging lens set 1 of the present invention. Please refer toFIG. 8A for the longitudinal spherical aberration on the image plane 71of the fourth example; please refer to FIG. 8B for the astigmaticaberration on the sagittal direction; please refer to FIG. 8C for theastigmatic aberration on the tangential direction, and please refer toFIG. 8D for the distortion aberration. The components in the fourthexample are similar to those in the first example, but the optical datasuch as the curvature radius, the refractive power, the lens thickness,the lens focal length, the aspheric surface or the back focal length inthis example are different from the optical data in the first example,and in this example, the first lens element has positive refractivepower; first image-side surface 12 of the first lens element 10 has aconvex part 16B in the vicinity of the optical axis and a concave part17B in a vicinity of its circular periphery; the second object-sidesurface 21 of the second lens element 20 has a convex part 23B in thevicinity of the optical axis and a concave part 24B in a vicinity of itscircular periphery; the sixth object-side surface 61 of the sixth lenselement 60 has a concave part 63B in the vicinity of the optical axisand a concave part 64B in a vicinity of its circular periphery. Theoptical data of the fourth example of the optical imaging lens set areshown in FIG. 24 while the aspheric surface data are shown in FIG. 25 .The length of the optical imaging lens set is 4.685 mm. HFOV is 66.5degrees. Some important ratios of the fourth example are as follows:

(G12+G34)/T6=1.134 T2/T3=0.328 EFL/G23=10.418 EFL/AAG=1.734AAG/BFL=2.316 EFL/T2=11.833 BFL/(G34+G45)=1.755 BFL/T1=2.604BFL/T2=2.946 AAG/T3=2.241 EFL/T1=10.460 AAG/T4=2.787 T4/T2=2.448T6/T2=2.534 Fifth Example

Please refer to FIG. 9 which illustrates the fifth example of theoptical imaging lens set 1 of the present invention. Please refer toFIG. 10A for the longitudinal spherical aberration on the image plane 71of the fifth example; please refer to FIG. 10B for the astigmaticaberration on the sagittal direction; please refer to FIG. 10C for theastigmatic aberration on the tangential direction, and please refer toFIG. 10D for the distortion aberration. The components in the fifthexample are similar to those in the first example, but the optical datasuch as the curvature radius, the refractive power, the lens thickness,the lens focal length, the aspheric surface or the back focal length inthis example are different from the optical data in the first exampleand in this example, the first object-side surface 11 of the first lenselement 10 has a concave part 13C in the vicinity of the optical axisand a concave part 14C in a vicinity of its circular periphery; thesixth image-side surface 62 of the sixth lens element 60 has a concavepart 66C in the vicinity of the optical axis, a concave part 67C in avicinity of its circular periphery, and a convex part 68C disposedbetween the concave part 66C and the concave part 67C. The optical dataof the fifth example of the optical imaging lens set are shown in FIG.26 while the aspheric surface data are shown in FIG. 27 . The length ofthe optical imaging lens set is 5.045 mm. HFOV is 66.5 degrees. Someimportant ratios of the fifth example are as follows:

(G12+G34)/T6=0.582 T2/T3=0.363 EFL/G23=9.138 EFL/AAG=2.797 AAG/BFL=0.882EFL/T2=7.738 BFL/(G34+G45)=5.118 BFL/T1=3.150 BFL/T2=3.137 AAG/T3=1.004EFL/T1=7.769 AAG/T4=0.430 T4/T2=6.431 T6/T2=2.258 Sixth Example

Please refer to FIG. 11 which illustrates the sixth example of theoptical imaging lens set 1 of the present invention. Please refer toFIG. 12A for the longitudinal spherical aberration on the image plane 71of the sixth example; please refer to FIG. 12B for the astigmaticaberration on the sagittal direction; please refer to FIG. 12C for theastigmatic aberration on the tangential direction, and please refer toFIG. 12D for the distortion aberration. The components in the sixthexample are similar to those in the first example, but the optical datasuch as the curvature radius, the refractive power, the lens thickness,the lens focal length, the aspheric surface or the back focal length inthis example are different from the optical data in the first example.The optical data of the sixth example of the optical imaging lens setare shown in FIG. 28 while the aspheric surface data are shown in FIG.29 . The length of the optical imaging lens set is 4.154 mm. HFOV is66.5 degrees. Some important ratios of the sixth example are as follows:

(G12+G34)/T6=0.612 T2/T3=2.248 EFL/G23=4.164 EFL/AAG=1.543 AAG/BFL=2.020EFL/T2=2.927 BFL/(G34+G45)=1.671 BFL/T1=2.212 BFL/T2=0.939 AAG/T3=4.263EFL/T1=6.896 AAG/T4=1.871 T4/T2=1.014 T6/T2=0.876 Seventh Example

Please refer to FIG. 13 which illustrates the seventh example of theoptical imaging lens set 1 of the present invention. Please refer toFIG. 14A for the longitudinal spherical aberration on the image plane 71of the seventh example; please refer to FIG. 14B for the astigmaticaberration on the sagittal direction; please refer to FIG. 14C for theastigmatic aberration on the tangential direction, and please refer toFIG. 14D for the distortion aberration. The components in the seventhexample are similar to those in the first example, but the optical datasuch as the curvature radius, the refractive power, the lens thickness,the lens focal length, the aspheric surface or the back focal length inthis example are different from the optical data in the first example,and in this example, the sixth image-side surface 62 of the sixth lenselement 60 has a concave part 66D in the vicinity of the optical axisand a concave part 67D in a vicinity of its circular periphery. Theoptical data of the seventh example of the optical imaging lens set areshown in FIG. 30 while the aspheric surface data are shown in FIG. 31 .The length of the optical imaging lens set is 4.163 mm. HFOV is 66.5degrees. Some important ratios of the seventh example are as follows:

(G12+G34)/T6=0.194 T2/T3=0.798 EFL/G23=3.114 EFL/AAG=1.638 AAG/BFL=1.974EFL/T2=5.907 BFL/(G34+G45)=1.890 BFL/T1=2.192 BFL/T2=1.827 AAG/T3=2.878EFL/T1=7.088 AAG/T4=1.929 T4/T2=1.870 T6/T2=2.497

Some important ratios in each example are shown in FIG. 32 .

In the light of the above examples, the inventors observe the followingfeatures:

1. The third lens element has positive refractive power, to provide theneeded refractive power for the optical imaging lens set.

2. The first image-side surface of the first lens element has a concavepart in a vicinity of its circular periphery; the second image-sidesurface of the second lens element has a concave part in a vicinity ofthe optical axis, the fourth object-side surface of the fourth lenselement has a convex part in a vicinity of its circular periphery, thefifth object-side surface of the fifth lens element has a concave partin a vicinity of the optical axis, the sixth image-side surface of thesixth lens element has a concave part in a vicinity of the optical axis,where each of the surfaces match each other, in order to improve theaberration.

3. The sixth lens element is made of plastic, helping to decrease themanufacturing cost and lightened the weight, besides, helping to formthe aspherical surface.

4. If further matching the second object-side surface of the second lenselement has a convex part in a vicinity of the optical axis, the secondimage-side surface of the second lens element has a concave part in avicinity of its circular periphery; the third object-side surface of thethird lens element has a convex part in a vicinity of the optical axisand a convex part in a vicinity of its circular periphery; the thirdimage-side surface of the third lens element has a convex part in avicinity of the optical axis and a convex part in a vicinity of itscircular periphery; the fourth object-side surface of the fourth lenselement has a convex part in a vicinity of the optical axis; the fourthimage-side surface of the fourth lens element has a convex part in avicinity of the optical axis and a convex part in a vicinity of itscircular periphery; the fifth object-side surface of the fifth lenselement has a concave part in a vicinity of its circular periphery; andthe fifth image-side surface of the fifth lens element has a concavepart in a vicinity of the optical axis, where each of the surfaces matcheach other, remaining good performance while decreasing the total lengthof the optical imaging lens set. Furthermore, if all of the lenselements are made of plastic, this can further help to decrease themanufacturing cost and lighten the weight, helping to form theaspherical surface.

In addition, the inventors discover that there are some better ratioranges for different data according to the above various importantratios. Better ratio ranges help the designers to design the betteroptical performance and an effectively reduced length of a practicallypossible optical imaging lens set. For example:

(1) Since the lens element become lighter and thinner, and the qualitydemands get higher and higher, so that the lens is designed to havedifferent shape surface in a vicinity of the optical axis and invicinity of its circular periphery, the thickness is different in thecentral part of the lens element or near the edge of the lens element.Considering the characteristic of light, the light which is emitted fromthe near-edge side of the lens element has the longer path and largerrefraction angle to focus onto the image plane. Moreover, the air gapsalso influence the quality of the optical imaging lens set. The presentinvention has larger HFOV, because decreasing EFL can further enlargethe HFOV, so that the present invention has smaller EFL. In addition,the first lens element and the second lens element have larger opticaleffective apertures. Therefore, if the shorter ratio of T1 and T2 aresmaller than EFL, large T1 and T2 can be avoid, and further decreasingthe total length of the optical imaging lens set. The present inventionsatisfies the relationships: 4.7≤EFL/T1 and 2.8≤EFL/T2. Besides,considering the relationship between the air gaps and EFL, the presentinvention satisfies the relationships: 3≤EFL/G23≤11 and 0.9≤EFL/AAG≤2.6.When those relationships are satisfied, the optical imaging lens set hasshorter total length, but still having good performance and simplemanufacturing process. Furthermore, when the relationship 3.5≤EFL/G23≤11is further satisfied, since having a shorter G23, so each component ofthe optical imaging lens set has a better arrangement, and increasingthe yield.

(2) BFL is the distance between the image-side surface of the sixth lenselement to an image plane along the optical axis. The present inventionneeds a space to accumulate components such as the filter, so BFL cannotbe shrunk unlimited. Besides, BFL influences the value of EFL, and EFLis also influenced by the thickness of lens element. Therefore, thepresent invention satisfies the relationships: AAG/BFL≤2.1,1.88≤BFL/(G34+G45)≤6, 1.5≤BFL/T1 and 1.4≤BFL/T2, when thoserelationships are satisfied, the optical imaging lens set has largerHFOV, but still has good performance. In addition, if further satisfyingthe relationship: 1.9≤BFL/T2, since the present invention has largerBEL, it has a simpler manufacturing process.

(3) Since G12, G34 and G56 are not limited by the surface shape ofadjacent surfaces, so G12, G34 and G56 can be shrunk more, so AAG canalso be shrunk too. AAG is a relatively large value, so if AAG isshrunk, the total length can be decreased effectively. The presentinvention satisfy the relationships: (G12+G34)/T6≤1.7, AAG/T3≤3.3 andAAG/T4≤2.8.

(4) As mentioned above, T2 can be shrunk more, so if the relationshipsof T2/T3≤1.5, 1≤T4/T2 and 1.1≤T6/T2 are satisfied, the optical imaginglens set has better arrangement.

(5) Preferably, the present invention further satisfies the followingrelationships: 0.01≤(G12+G34)/T6≤1.7, 0.01≤T2/T3≤1.5, 0.4≤AAG/BFL≤2.1,2.8≤EFL/T2≤12, 1.5≤BFL/T1≤3.5, 1.4≤BFL/T2≤4, 0.3≤AAG/T3≤3.3,4.7≤EFL/T1≤12, 0.05≤AAG/T4≤2.8, 1≤T4/T2≤7 and 1.1≤T6/T2≤3.

The optical imaging lens set 1 of the present invention may be appliedto an electronic device, such as game consoles or driving recorders.Please refer to FIG. 16 . FIG. 16 illustrates a first preferred exampleof the optical imaging lens set 1 of the present invention for use in aportable electronic device 100. The electronic device 100 includes acase 110, and an image module 120 mounted in the case 110. A drivingrecorder is illustrated in FIG. 16 as an example, but the electronicdevice 100 is not limited to a driving recorder.

As shown in FIG. 16 , the image module 120 includes the optical imaginglens set 1 as described above. FIG. 16 illustrates the aforementionedfirst example of the optical imaging lens set 1. In addition, theportable electronic device 100 also contains a barrel 130 for theinstallation of the optical imaging lens set 1, a module housing unit140 for the installation of the barrel 130, a substrate 172 for theinstallation of the module housing unit 140 and an image sensor 70disposed at the substrate 172, and at the image side 3 of the opticalimaging lens set 1. The image sensor 70 in the optical imaging lens set1 may be an electronic photosensitive element, such as a charge coupleddevice or a complementary metal oxide semiconductor element. The imageplane 71 forms at the image sensor 70.

The image sensor 70 used here is a product of chip on board (COB)package rather than a product of the conventional chip scale package(CSP) so it is directly attached to the substrate 172, and protectiveglass is not needed in front of the image sensor 70 in the opticalimaging lens set 1, but the present invention is not limited to this.

To be noticed in particular, the optional filter 72 may be omitted inother examples although the optional filter 72 is present in thisexample. The case 110, the barrel 130, and/or the module housing unit140 may be a single element or consist of a plurality of elements, butthe present invention is not limited to this.

Each one of the six lens elements 10, 20, 30, 40, 50 and 60 withrefractive power is installed in the barrel 130 with air gaps disposedbetween two adjacent lens elements in an exemplary way. The modulehousing unit 140 has a lens element housing 141, and an image sensorhousing 146 installed between the lens element housing 141 and the imagesensor 70. However in other examples, the image sensor housing 146 isoptional. The barrel 130 is installed coaxially along with the lenselement housing 141 along the axis I-I′, and the barrel 130 is providedinside of the lens element housing 141.

Please also refer to FIG. 17 for another application of theaforementioned optical imaging lens set 1 in a portable electronicdevice 200 in the second preferred example. The main differences betweenthe portable electronic device 200 in the second preferred example andthe portable electronic device 100 in the first preferred example are:the lens element housing 141 has a first seat element 142, a second seatelement 143, a coil 144 and a magnetic component 145. The first seatelement 142 is for the installation of the barrel 130, exteriorlyattached to the barrel 130 and disposed along the axis I-I′. The secondseat element 143 is disposed along the axis I-I′ and surrounds theexterior of the first seat element 142. The coil 144 is provided betweenthe outside of the first seat element 142 and the inside of the secondseat element 143. The magnetic component 145 is disposed between theoutside of the coil 144 and the inside of the second seat element 143.

The first seat element 142 may pull the barrel 130 and the opticalimaging lens set 1 which is disposed inside of the barrel 130 to movealong the axis I-I′, namely the optical axis 4 in FIG. 1 . The imagesensor housing 146 is attached to the second seat element 143. Thefilter 72, such as an infrared filter, is installed at the image sensorhousing 146. Other details of the portable electronic device 200 in thesecond preferred example are similar to those of the portable electronicdevice 100 in the first preferred example so they are not elaboratedagain.

Those skilled in the art will readily observe that numerousmodifications and alterations of the device and method may be made whileretaining the teachings of the invention. Accordingly, the abovedisclosure should be construed as limited only by the metes and boundsof the appended claims.

What is claimed is:
 1. An optical imaging lens, from an object side toan image side in order along an optical axis, comprising a first lenselement, a second lens element, a third lens element, a fourth lenselement, a fifth lens element, and a sixth lens element, each of thefirst, second, third, fourth, fifth, and sixth lens elements having anobject-side surface facing toward the object side and an image-sidesurface facing toward the image side, the optical imaging lens does notinclude any lens element other than the first lens element, the secondlens element, the third lens element, the fourth lens element, the fifthlens element, and the sixth lens element, wherein: the object-sidesurface of the first lens element has a convex part in a vicinity of theperiphery of the first lens element; the image-side surface of thesecond lens element has a concave part in a vicinity of the periphery ofthe first lens element; the object-side surface of the third lenselement has a convex part in a vicinity of the optical axis; theimage-side surface of the fourth lens element has a convex part in avicinity of the periphery of the fourth lens element; the image-sidesurface of the fifth lens element has a concave part in a vicinity ofthe optical axis; and the sixth lens element has negative refractivepower.
 2. The optical imaging lens of claim 1, wherein EFL is aneffective focal length of the optical imaging lens, T2 is a thickness ofthe second lens element along the optical axis, and the optical imaginglens satisfies the relation: 2.8≤EFL/T2.
 3. The optical imaging lens ofclaim 1, wherein AAG is a sum of all air gaps from the first lenselement to the sixth lens element along the optical axis, BFL is adistance between the image-side surface of the sixth lens element and animage plane along the optical axis, and the optical imaging lenssatisfies the relation: AAG/BFL≤2.1.
 4. The optical imaging lens ofclaim 1, wherein T2 is a thickness of the second lens element along theoptical axis, T3 is a thickness of the third lens element along theoptical axis, and the optical imaging lens satisfies the relation:T2/T3≤1.5.
 5. The optical imaging lens of claim 1, wherein T3 is athickness of the third lens element along the optical axis, T4 is athickness of the fourth lens element along the optical axis, T1 is athickness of the first lens element along the optical axis, G12 is anair gap between the first lens element and the second lens element alongthe optical axis, T2 is a thickness of the second lens element along theoptical axis, and the optical imaging lens satisfies the relation:0.613≤(T3+T4)/(T1+G12+T2)≤2.931.
 6. The optical imaging lens of claim 1,wherein TTL is a distance between the object-side surface of the firstlens element and an image plane along the optical axis, BFL is adistance between the image-side surface of the sixth lens element and animage plane, T1 is a thickness of the first lens element along theoptical axis, T6 is a thickness of the sixth lens element along theoptical axis, and the optical imaging lens satisfies the relation:3.604≤(TTL-BFL)/(T1+T6)≤6.280.
 7. The optical imaging lens of claim 1,wherein the object-side surface of the first lens element has a convexpart in a vicinity of the optical axis.
 8. An optical imaging lens, froman object side to an image side in order along an optical axis,comprising a first lens element, a second lens element, a third lenselement, a fourth lens element, a fifth lens element, and a sixth lenselement, each of the first, second, third, fourth, fifth, and sixth lenselements having an object-side surface facing toward the object side andan image-side surface facing toward the image side, the optical imaginglens does not include any lens element other than the first lenselement, the second lens element, the third lens element, the fourthlens element, the fifth lens element, and the sixth lens element,wherein: the object-side surface of the first lens element has a convexpart in a vicinity of the periphery of the first lens element; theimage-side surface of the second lens element has a concave part in avicinity of the periphery of the second lens element; the object-sidesurface of the third lens element has a convex part in a vicinity of theoptical axis; the image-side surface of the fourth lens element has aconvex part in a vicinity of the periphery of the fourth lens element;and the object-side surface of the sixth lens element has a convex partin a vicinity of the periphery of the sixth lens element and theimage-side surface of the sixth lens element has a concave part in avicinity of the optical axis.
 9. The optical imaging lens of claim 8,wherein G12 is an air gap between the first lens element and the secondlens element along the optical axis, G34 is an air gap between the thirdlens element and the fourth lens element along the optical axis, T6 is athickness of the sixth lens element along the optical axis, and theoptical imaging lens satisfies the relation: 0.193≤(G12+G34)/T6≤1.667.10. The optical imaging lens of claim 8, wherein EFL is an effectivefocal length of the optical imaging lens, T2 is a thickness of thesecond lens element along the optical axis, and the optical imaging lenssatisfies the relation: 2.8≤EFL/T2.
 11. The optical imaging lens ofclaim 8, wherein AAG is a sum of all air gaps from the first lenselement to the sixth lens element along the optical axis, T3 is athickness of the third lens element along the optical axis, and theoptical imaging lens satisfies the relation: AAG/T3≤3.3.
 12. The opticalimaging lens of claim 8, wherein BFL is a distance between theimage-side surface of the sixth lens element and an image plane alongthe optical axis, T1 is a thickness of the first lens element along theoptical axis, and the optical imaging lens satisfies the relation:1.5≤BFL/T1.
 13. The optical imaging lens of claim 8, wherein theimage-side surface of the sixth lens element has a convex part in avicinity of the periphery of the sixth lens element.
 14. The opticalimaging lens of claim 8, wherein the object-side surface of the secondlens element has a convex part in a vicinity of the optical axis.
 15. Anoptical imaging lens, from an object side to an image side in orderalong an optical axis, comprising a first lens element, a second lenselement, a third lens element, a fourth lens element, a fifth lenselement, and a sixth lens element, each of the first, second, third,fourth, fifth, and sixth lens elements having an object-side surfacefacing toward the object side and an image-side surface facing towardthe image side, the optical imaging lens does not include any lenselement with refractive power other than the first lens element, thesecond lens element, the third lens element, the fourth lens element,the fifth lens element, and the sixth lens element, wherein: theimage-side surface of the second lens element has a concave part in avicinity of the periphery of the second lens element; the object-sidesurface of the third lens element has a convex part in a vicinity of theoptical axis; the image-side surface of the fourth lens element has aconvex part in a vicinity of the periphery of the fourth lens element;the object-side surface of the fifth lens element has a concave part ina vicinity of the periphery of the fifth lens element and the image-sidesurface of the fifth lens element has a concave part in a vicinity ofthe optical axis; the object-side surface of the sixth lens element hasa convex part in a vicinity of the optical axis; and the image-sidesurface of the sixth lens element has a concave part in a vicinity ofthe optical axis.
 16. The optical imaging lens of claim 15, wherein ALTis a sum of thicknesses of the six lens element from the first lenselement to the sixth lens element along the optical axis, BFL is adistance between the image-side surface of the sixth lens element and animage plane along the optical axis, T1 is a thickness of the first lenselement along the optical axis, G23 is an air gap between the secondlens element and the third lens element along the optical axis, and theoptical imaging lens satisfies the relation:3.304≤(ALT+BFL)/(T1+G23)≤6.111.
 17. The optical imaging lens of claim15, wherein TTL is a distance between the object-side surface of thefirst lens element and an image plane along the optical axis, BFL adistance between the image-side surface of the sixth lens element and animage plane along the optical axis, G23 is an air gap between the secondlens element and the third lens element along the optical axis, G34 isan air gap between the third lens element and the fourth lens elementalong the optical axis, and the optical imaging lens satisfies therelation: 5.189 (TTL−BFL)/(G23+G34)≤11.099.
 18. The optical imaging lensof claim 15, wherein TTL is a distance between the object-side surfaceof the first lens element and an image plane along the optical axis, BFLis a distance between the image-side surface of the sixth lens elementand an image plane along the optical axis, T2 is a thickness of thesecond lens element along the optical axis, G45 is an air gap betweenthe fourth lens element and the fifth lens element along the opticalaxis, and the optical imaging lens satisfies the relation:5.809≤(TTL−BFL)/(T2+G45)≤10.608.
 19. The optical imaging lens of claim15, wherein AAG is a sum of all air gaps from the first lens element tothe sixth lens element along the optical axis, BFL is a distance betweenthe image-side surface of the sixth lens element and an image planealong the optical axis, and the optical imaging lens satisfies therelation: AAG/BFL≤2.1.
 20. The optical imaging lens of claim 15, whereinthe image-side surface of the third lens element has a convex part in avicinity of the periphery of the third lens element.